EP 0878456 A1 19981118 - Process for the preparation of p-bromotoluene
Title (en)
Process for the preparation of p-bromotoluene
Title (de)
Verfahren zur Herstellung von p-Bromtoluol
Title (fr)
Procédé pour la préparation de p-bromotoluène
Publication
Application
Priority
- EP 97250155 A 19970514
- US 7838098 A 19980513
Abstract (en)
A crude bromotoluene mixture comprising at least 70 wt% of a mixture of p-bromotoluene and o-bromotoluene, and wherein the weight ratio of p-bromotoluene:o-bromotoluene is in the range of 50:50 to 99:1 is cooled to a temperature at which crystals of product enriched in p-bromotoluene are formed in a first residual mother liquor. After removing the residual mother liquor from the crystals of product enriched in p-bromotoluene, the crystals are partially melted to form a mixture of residual higher purity p-bromotoluene in the form of crystals, and a second mother liquor having a higher content of o-bromotoluene than said first residual mother liquor. This higher purity p-bromotoluene and the second mother liquor are separated from each other. The entire procedure starting with the above cooling step can be repeated as a second stage and again as a third stage each time using as the initial feed the residual higher purity p-bromotoluene that is separated from the second mother liquor of the preceding stage. Product of 99.5 wt% purity can be formed in this manner. <IMAGE>
IPC 1-7
IPC 8 full level
C07C 17/392 (2006.01); C07C 25/02 (2006.01)
CPC (source: EP US)
C07C 17/392 (2013.01 - EP US); C07C 25/02 (2013.01 - EP US)
Citation (search report)
- [A] GB 1066032 A 19670419 - EXPL DES PROCEDES AB DER HALDE
- [A] DATABASE WPI Section Ch Week 9250, Derwent World Patents Index; Class C03, AN 92-411568, XP002041906
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
DOCDB simple family (application)
EP 97250155 A 19970514; US 7838098 A 19980513